The poxviruses (family Poxyiridae) cause illness characterized by generalized or localized cutaneous lesions and most member viruses have broad host ranges. The overall broad host range of this family is evident by the two subfamilies of the Poxyiridae. The subfamily Entornopoxyirinae infects insects and the subfamily Chordopoxyirinae (chordopoxviruses) infects vertebrates, with the latter encompassing eight classified genera, and other “unclassified chordopoxviruses.” The classified genera are: Orthopoxvirus, Parapoxvirus, Avipoxvirus, Capripoxvirus, Leporipoxvirus, Suipoxvirus, Molluscipoxvirus, and Yatapoxvirus.
Poxvirus infections of humans, cattle, sheep, goats, companion animals, birds and zoo animals have been reported worldwide (Damon, “Poxvirus” in Field Virology 5th edition, 2947-2976, David M. Knipe, ed.) but in general represent an underappreciated cause of healthcare utilization. Indeed, within the U.S., ICD codes were not available for many of these virus infections until recently. However, the degree to which poxvirus result in patients seeking medical treatment has begun to be defined. One recent study determined that 22/10,000 healthcare visits could be attributed to Molluscum contagiosum infections (Reynolds et. al., PloS One, 4:e5255, 2009).
Poxviruses are often the unrecognized source of many emerging or reemerging infections in various parts of the world, and are often clinically confused with other cutaneous diseases. Because the majority of human poxvirus infections are zoonotic, such infections place a significant burden on agricultural communities. Capripoxvirus infections of ruminants cause significant morbidity and mortality. Parapoxvirus infections of ruminants and their handlers are endemic in the U.S. and worldwide; and infected humans often turn to veterinarians for diagnostic assistance (Lederman et al., Ped. Infect. Dis. J., 26:740-744, 2007). In another example, human monkeypox (an orthopoxvirus) is an emerging infection with smallpox-like characteristics that was introduced into the U.S. in 2003 via global commerce in the exotic pet animal trade. The evolution of monkeypox virus and its two major clades in Africa represents an incompletely understood emerging infectious risk. Additionally, although smallpox, caused by variola virus, is an eradicated disease, it remains a significant biothreat agent of international concern, and is the subject of World Health Organization-approved research activities.
Over the past five years, an increasing number of potential poxvirus therapies have been studied. However, better diagnostic methods of identifying poxviruses are necessary in order to determine the cause of cutaneous infections, and decrease their inappropriate treatment. For instance, parapoxvirus infections are often misdiagnosed as cutaneous anthrax, which unnecessarily contributes to overuse of antibacterial agents. There is therefore a demonstrated need to develop better diagnostic tools to detect and identify the agent of poxvirus infections.